The company blames increased political and regulatory uncertainty, a potential tariff cap, and warmer than normal weather, for the poor end to its 2017 accounts.

Iain Conn, Group Chief Exec said:

“Our financial result in the second half of 2017 was weak, primarily reflecting poor performance in Business energy supply and particularly in our North America Business unit.

“The combination of political and regulatory intervention in the UK energy market, concerns over the loss of energy customers in the UK, and the performance issue in North America have created material uncertainty around Centrica and, although we delivered on our financial targets for the year, this resulted in a very poor shareholder experience.

“We regret this deeply, and I am determined to restore shareholder value and confidence. The underlying trends driving our strategy are clear, as are the distinctive capabilities we have to benefit from them.

“We are committed to delivering attractive returns and growth over the medium term. Our focus today is on performance delivery and financial discipline – on demonstrating top line growth as we deliver improved service and new propositions for our customers, and driving efficiency as hard as possible to underpin our competitiveness”.